promiseChainExplore.js

Promise.resolve("original")
.then(
    resolved => {
        console.log(`Upper Promise resolved, message is "${resolved}"`);
        throw "stage1 throw error"; // -> This thrown error will trigger the following then()'s rejected function, but not in this then()'s rejection.
        return "stage1 succeed";
    },
    rejected => {
        console.log(`Upper Promise rejected, message is "${rejected}"`);
        // throw "stage1 failed" // -> will let the following then() receive a rejected Promise with this string
        return "stage1 failed"; // -> will let the following then() receive a resolved Promise with this string 
    }
)
.then(
    resolved => {
        console.log(`Upper Promise resolved, message is "${resolved}"`);
        return "stage2 succeed";
    },
    rejected => {
        console.log(`Upper Promise rejected, message is "${rejected}"`);
        return "stage2 failed";
    }
);